controlling the spread of contour lines

I have the following code which plots a filled contour. I want more closed contours towards the center of the figure because they are more important to me. How can I control the spacing of the contour lines?

% Function to plot contours
x1=-5:0.1:5;
x2=-5:0.1:5;
[a ,b]=meshgrid(x1,x2);
f=(2.*(a).^2)-(1.05.*(a).^4)+((a.^6)./6)+(a.*b)+(b.^2);
[c,h]=contourf(a,b,f,20);
clabel(c,h);

Answer 1

[Star Strider]

You can define the contour levels with a vector.

Example —

% Function to plot contours
x1=-5:0.1:5;
x2=-5:0.1:5;
[a ,b]=meshgrid(x1,x2);
f=(2.*(a).^2)-(1.05.*(a).^4)+((a.^6)./6)+(a.*b)+(b.^2);
lvls = exp(-10:0.1:7.5);                                    % Define Contour Levels
[c,h]=contourf(a,b,f,lvls);
clabel(c,h);

The ‘lvls’ vector creates an exponentially-increasing set of contours. You can use any vector you want.